Go right ahead! There's nothing stopping you.
We have a few "rules", though:
4)Try to keep canon characters "in character".
5)If you're going to use someone else's Lego, advanced warning is preferred. However, if the owner of that Lego does not respond within a reasonable time, then go ahead and run with it.
6)Sex has to be well written. (This means that things have to be physically possible, enjoyed by all parties, and body parts have to act like they do in the Real World (TM).)
As it stands right now, we have the students (in order of creation, IIRC):
Harry, Draco, Hermione, Colin, Ron, Ginny, Neville, Pansy
and assorted others:
Tom, Lucius, Sirius, Myrtle & the squid.
Now... some of us know some of us, but none of us know ALL of us. And until now, Out of Character posts were kept locked to Friends Only --which is why the Legos only "friend" other Legos. We will likely continue to use that tool for creating secret plots amongst ourselves so we can surprise & amaze our fans & followers with our views of Life at Hogwarts.
But here ...here we can talk "outside the toy box" and get input & suggestions from the rest of you.